Drive-in fan



Nov. 26, 1-957 G. v. EISERMAN 2,814,432

DRIVE-IN FAN Filed Oct. 14, 1955 INVENTOR GERT V. EISERMAN ATTORNEYS ni ed States Patent" DRIVE-IN FAN Gert V; Eiserman, Beacon, N. Y., assignor to The Green Fuel Economizer Co. Inc., Beacon, N. Y.

Application October 14, 1955, Serial No. 540,521

1 Claim. (Cl. 230-117) The present invention concerns a compact dual wheel, single motor impeller fan.

It is an object of the invention to provide a fan with a single motor which has the only shaft in the assembly, whereby an expensive wheel shaft may be eliminated.

It is an object of the invention to provide a fan in which the motor bearings also comprise the fan bearings, thus eliminating expensive bearings normally mounted on the outside of the housing.

It is an object of the invention to provide a dual wheel fan in which the cost of coupling or other drive connections between the motor fan and the fan shaft, normal in such constructions, is eliminated.

It is an object of the invention to provide a dual wheel in which the fan pedestals and sole plates and other bearing supports, are eliminated, and the angle iron frame at the bottom of the housing, normally supplied with the fan, may be bolted and grouted to the floor at a minimum of expense.

It is an object of the invention to provide an inexpensive dual fan in which separate foundation and pedestals for the motor are eliminated.

It is an object of the invention to provide a dual wheel fan in which forced circulation of air through the motor can be obtained, which provides sufficient cooling whereby it is in many cases possible to increase the rating of the motor by as much as 50%.

It is an object of the invention to provide a dual fan in which the distance between the back-plates of the two fan wheels may be set so as to give best distribution of gas over the entire fan scroll cross-sectional area, yielding a reduced friction loss through the entire fan.

The invention may take the form of a double inlet, double Width centrifugal fan housing with two impellers mounted on opposite sides of a motor and on the motor shaft itself, the motor shaft providing two end shaft stubs one on each side of the motor on which the impeller fan wheels are mounted. In this assembly, the motor is preferably mounted through or near the center line of the housing scroll with a motor mounting flange either through or near the center line between the motor shaft ends; or the mounting may be moved to one side of the motor housing if desired.

It is an object of the invention to provide impeller fan wheels having back-plates with holes near the hub in order to provide circulation of air around the motor from the housing, and back into the impeller inlet. This construction gives forced ventilation and cooling of the motor, and its bearings, as mentioned above.

It is an object of the invention to provide a compact, inexpensive, dual fan assembly in which the width of the housing is determined principally by the diameter of the fan Wheel itself; and by the employment of the present invention, this width may be reduced to less than twice the diameter of the fan wheels, giving an improved construction of increased efficiency and saving space.

In the drawings, like numerals refer to like parts throughout:

ice

Figure 1 is a front elevation of one form of the invention; and

Figure 2 is a side elevation of the construction shown in Figure 1.

The fan housing 10 comprises a scroll-shaped member 11 having a convolution of increasing radius leading to the outlet 12 which may be flanged as at 13, for connection to other equipment. The outlet has a center line 14 displaced from a center line 15 on which lies the point of origin of the scroll 11. The upper part of the housing comprising outlet 12, is formed by a square or rectangular construction 16, which is joined by a wall structure of suitable descriptive geometry to the scroll conformation 11. A transverse center line 17, which passes through the center of generation of scroll 11, determines the position of dual air inlets 18 and 19 disposed on opposite sides of the housing and preferably being symmetrical about the center line 17.

The motor 20 is mounted centrally within the housing along the center line 17 and midway between the inlets 18 and 19. Inlets 18 and 19 may be provided with a suitable curved air guide 21 leading to air inlet channel 22 in which can be positioned a series of movable vanes 23 for controlling the flow of inlet air. Motor 20 is mounted on a support 24 which may be a plurality of structural members, or a plate centrally positioned within the housing 10. Motor 20 may be of a compact pancake or standard type, and the plate 24 provides its sole mounting. The shaft 25 extends through the motor and is double-ended, as shown in Figure 1. Each stub 25 carries thereon impeller fan wheels 26 which have their intake sides facing inlets 18 and 19. Fan wheels 26 may be provided with back-plates 27 having holes or annular channels 28 adjacent the motor, to permit the passage of air. As the fan rotates, the fan wheels draw air through the inlets 18 and 19, as permitted by the vanes 23, depending upon their angular position. Air is forced out radially by the blades of fan wheels 26 so that it follows along the scroll 11 in the direction of rotation, and into the outlet 12.

It will be noted that the back-plates 27 are quite close together so that the fiow of air from the two separate fan wheels forms two streams which flow smoothly together with a minimum of turbulence. If desired, the fan wheels can be placed even closer together, as shown in Figure 1, so that the back-plates are separated by a. distance which is determined principally by the thickness of motor support 24 and the necessary clearance for rotation. As the fan wheels 26 rotate, it will be noted that they develop an area of low pressure adjacent their hubs so that air is drawn from the scroll 11 over the motor and through any perforations in the motor casing so that a good circulation of cooling air through the motor is obtained. This air passes through the annular channels 28 and is again forced radially outward by the fan wheels 26.

It will be understood that where the compact pancake motor is used, as shown in the drawings, flat back-plates may be used with it. On the other hand, standard or pancake motors may require that the back-plates be curved to a greater or lesser degree.

It is well known that the rating of motors depends principally upon their capacity to dissipate heat; and it has been found by actual test that the motors utilized in this assembly have been able to handle half again the load for which they are normally rated. In some cases where the air being pumped is relatively cool, this increase in capacity has been found to exceed 50%.

While there has been described above what is at present believed to be the preferred form of the invention, the appended claim is intended to include all variations thereof which fall within the true spirit of the invention.

I claim:

A dual centrifugal impeller fan comprising a housing, having dual oppositely disposed inlets therein, a pancake type motor having a double-ended shaft centrally mounted within said housing between said inlets, an impeller mounted on each end of said motor shaft, said housing being in scroll form and having an outlet which receives air from said impellers along an axis offset from the center of said scroll and substantially normal to the axis of said inlets, and combines the air from both said streams into a single smooth stream, a mounting plate for said motor adjacent the center line of said housing scroll and mounting said motor in the air stream, back-plates for said impellers, said back-plates being coextensive with said impellers and having holes therein adjacent said shaft ends for providing forced circulation of air flow around the motor from the housing, the blades of said impeller being spaced apart a distance less than the width of the motor whereby air distribution at the outlet is improved, friction loss is reduced and a compact structure is achieved.

References Cited in the file of this patent UNITED STATES PATENTS 2,235,050 Thege et a1. Mar. 18, 1941 2,297,050 Cotton et a1. Sept. 28, 1942 2,325,222 Bretzlotf et a1 July 27, 1943 2,710,573 Marker June 14, 1955 FOREIGN PATENTS 15,659 Great Britain July 5, 1909 

